1. Field of the Invention
The present invention relates to a display control device for a touch panel-type setting-operation unit, which is designed to display a plurality of manually operable keys on a display screen and to perform an input processing corresponding to the operation of one or more of the keys. The present invention also relates to an electronic apparatus, such as an image forming apparatus, which is equipped with the display control device.
2. Description of the Related Art
Heretofore, an operation panel for copying machines or facsimile machines has been provides with a display control device for a touch panel-type setting-operation unit, which designed to display a plurality of manually operable input keys on a display screen such as liquid-crystal display or CRT display, and, in response to an operator's finger-touch on one of the keys displayed on the screen, to allow an operational instruction corresponding to the touched key to be entered therethrough.
For example, in a facsimile machine having a touch panel, there has been known one type in which a plurality of one-touch or touch-sensitive keys indicative of 20 to 30 of designation telephone numbers are displayed on the screen of the touch panel, and the screen can be switched over to register 100 or more of designation telephone numbers. The functions of the one-touch keys provide a simplified operational procedure for transmitting to a frequently used destination, and an improved operationality or usability of the facsimile machine. There has also been proposed a technique in which the number of uses of each of a plurality of destinations is counted every time a corresponding one-touch key is operated, and a higher priority is given to the destination used in a higher frequency on the basis of the counted number of uses so as to sequentially change the respective display positions of the destinations in the order of descending priorities to allow the frequently used designation to be displayed on the first one of a plurality of switchable screens of a touch panel (see Japanese Patent Laid-Open Publication No. 04-225673).
However, as in the above facsimile machine, if the respective display positions of the destinations to be displayed on the touch panel screens are sequentially changed in response to the frequency of use in the corresponding one-touch keys, there will be difficulties for a user to find the position of a key to be used, resulting in adversely deteriorated usability.